The thermostat in my Vectra is marked 93/107°. I've put it in boiling water, but even adding some salt, I can only get it to 102°. The thermostat still dosent open. I've put a new one in anyway, but its the same. Is it possible to check for correct operation

trover, April 2009

The radiator had to be replaced after the header tank developed a huge crack. I assume the crack is because the airconditioning condenser and fan are supported by moulded brackets on the same header tank. The car was not overheating, but whenever problems of this nature arise, one checks the thermostat in case the crack is due to excess pressure from overheating, but I am unable to see it open when immersed in boiling salty water. The new thermostat I bought is the same. I guess the engine runs at a higher temperature than most cars. I replaced the thrermostat anyway, so I'll try the old one in an oven - nothing to loose there. Changing the radiator has been a much larger task than it normally is on other cars - what were they thinking. Thanks for the reply

trover, April 2009

The 'stat should be opening at102 deg.
Try putting it in the oven at 120 (just out of curiosity!!)
When you say the new one is the same, do you mean you tested it in boiling water and it did not open, or you fitted it in the car and you are still having running problems (overheating, I assume)?
If the latter, please post the actual symptoms.

trey, April 2009